Highly stretchable yarn



Oct. 23, 1945. B, H, FOSTER 4 2,387,320

HIGHLY STRETCHABLE YARN Filed Aug. 5, 1944 INVENTOR. 5w/wia H. Fam/75Hi'gi 7 BVM 3- A TTORNEY Patented Oct. 23 1945l HIGHLY STRTCHABLE YARNvBoutwell H. Foster, Maplewood, N. J., assgnor to United States RubberCompany, New York, N. Y., a corporation of New Jersey Application August5, 1944, Serial No. 548.268

9 Claims. (Ci. 57--139) 4 This invention relates to an all-textile yarnhaving high stretch characteristics so that it will stretch and contractvery much like an elastic yarn having a rubber core.

lHigh stretch or crepe yarns are well known and have been extensivelyused heretofore, the amount oftwist imparted to such .yarns is usuallytwo or three times that of ordinary yarn of the same material.` Thesecrepe yarns as constructed heretoance and loss of time.

The present invention contemplates an all-textile yarn having stretchcharacteristics or an elastic extensibility range which may be muchgreater than that of the crepe yarns employed heretofore, and thisincreased stretch range is secured without imparting to the yarn acorresponding inl crease in the tendency of the same to kink or snarl.

In carrying out the present invention a crepe yarn is employed which maybe a single yarn having a crepe twist, or it may be two or more single`yarns plied together with a crepe twist. Such a crepe yarn, inaccordance with the present invention, is coiled helically aboutacentral axis in the same direction in which this yarn is highly twisted.The effect of this is to impart to the yarn a high number. of coils orwraps in addition to its high twist, so that these wraps will materiallyincrease the range of stretch of the yarn over that imparted by the hightwist alone. The helical coils impart alongcontrolled stretch to theyarn and give it a good kick or contractive action. Such a yarn having ahigh twist and a high number of coils has a better contractive forcethan the usual crepe yarn, and while it may still l tend to kink thenumerous small coils disperse the kinks and thereby keep them so smallthat they will easily pull out when the yarn is tensioned.

The highly twisted and coiled yarn contemplated bythe present inventionmay be balanced `or` unbalanced and it may be formed of cotton,

wool, rayon, silk, nylon or other well known or preferred yarn, and theelastic extensibility range imparted to the yarn by the presentinvention may be controlled to provide any desired stretchrange from 50%to 300% or more as desired.

An important feature of the invention resides in the constructionwhereby the range of stretch imparted to the present yarn may becontrolled accurately. This may be done by winding a crepe yarn incontacting coils about a small core yarn to provide a yarn having onerange of stretch, and by winding a similar yarn about a larger core yarnto provide a yarn with a greater range of stretch. The purpose of thecore yarn is 'to determine the size of the coils and such core yarn islater destroyed so that the twisted and wrapped yarn will be free tostretch. It will be understood that the larger the coils thelgreater theyarn can stretch as these coils straighten out, and that a correspondingreduction in the added twist will occur as the coils are increased insize.

The present yarn when in the relaxed, shrunk or contracted conditionwill have a large number of ne helical coils in addition to its hightwist, but to secure the results herein contemplated it is importantthat the helical coils shall extend in the direction in which the yarnis twisted so that the twist of the yarn will increase as the coils arestraightened out and the twist of the yarn will decrease as the yarncontractsand again assumes y its helical condition.

The yarn having the novel `construction so far described will beunbalanced and when free from tension will kink up to some extent, butthis is found not to be serious because, as above stated the coils tendto disperse the kinks so that they will pull out readily when tensioned.

"The highly stretchable unbalancedyarn of the present invention can bebalanced by wrapping a second highly twisted yarn in the oppositedirection over therst helically wound yarn, or a balanced constructioncan be produced by taking the unbalanced highly twisted and highlycoiled yarn just described and plying two such yarns together so thattheir ply twist wil be in the opposite direction to that in which theyarns are coiled.

The-above and other features of the present invention will be more fullyunderstood from the following description when read in connection withthe accompanying drawing, wherein:

Fig. 1 is a side elevation of an unbalanced yarn constructed inaccordance with the present invenden and comprises a highly twisted plywound helically about a core yarn. v

Fig. 1 after Fig. '2 shows the construction of the core yarn has beenremoved and the highly twisted helically wound yarn has been partlystretched. i A j Y Fig. 3 is a sectional view taken on aI-line 3--3 ofFig.' 2. v .Y

Fig. 4 is a side elevation of a balanced yarn constructed-in accordancewith the' present' invention and comprises one twisted and coiled yarnforming an inner cover about which a second twisted yarn is wrapped asan outer cover.

Fig. 5 shows' the construction otFig. 4 after the core yarn has beenremoved and the remaining balanced yarn is partly stretched.

Fig. 6 is a' sectional view taken on the line 6-6 of Fig. 5.

Fig. 'I is a side-elevation of a modification showing a balancedstretchable yarn formed by ply twisting together two yarns such as shownin Fig. 1; and v Fig. 8 is a sectional view takenon the line 8--8 A verysimple formof the present invention resides in the unbalanced twistedand coiled yarn shown in Figs. 1, 2 and 3 of the drawing. 'I'he balancedconstruction shown in Figs. 4, 5 and 6 is easily produced by winding asecond highly twisted yarn spirally about 4rthe construction shown inFig. 1 but in the opposite direction to the yarn whereby a yarn fhavingany desired stretch and flrst windings; and the balanced constructionwell-known textile fibres or filaments. Such yarn which is designated byI0 in the drawing i's shown as a ply yarn formed by twisting togethertwo ordinary yarns II. The twist imparted to .th`e yarn I0 is a 'hightwist or crepe twist which is preferably two or three times as high asthat of the ordinary yarn of the same material. The

good contractive action lthroughout a ran e of from to 300% or more canbe prod ced. This stretch control is secured by varying the size of thecore used. For example in experilmentingin this fleld a cotton yarn suchas 1 end of 80 S/2 was used as the crepe yarn and this was woundtightly'about 1 end of 150 denier acetate yarn, asshown in Fig. 1 of thedrawing, this produced a twisted andr coiled yarn having about a 100%stretch. Next the same. type of crepe.J

cotton yarn was similarly wound around a core formed of two of theacetate yarns just described,

, and this produced a twisted and coiled yarn having about a 200%stretch.l Likewise whenthree of these acetate yarns were used in thecore about have the desired coils I2 imparted thereto by employing theapparatus shown in the Gammeter Pat. No. 1,982,208 so that the yarn I0may be wound helically upon the needle shown in theI Gammeter patent.After the yarn I0 is wound upon such needle it may be progressivelyremoved therefrom by slipping it endwise of the needle off of its freeend, so as to produce a coiled yarn having. an opening at the center asshown in Fig. 3. This clearly discernible opening at the center of thecoils is an essential feature ofthe present invention. Therefore whenthe present twisted and coiled yarn isI relieved from tension thediameter of a coil I2 will always be more number of twist per unitlength imparted to the yarn I0 may however vary considerably depende itwist of the individual strands I I.

As soon as'the desired high twist or crepe twist has been imparted tothe yarn I0 it may be coiled helically about a central axis in thedirection of its twist to form the helical coils I2, and itis extremelyimportant that the coils I2 be wound in the same direction in which theyarn I0 is twisted. For example, if the strands I I have whatis known asa Z twist then the yarn I0 should have an S twist and the coils I2likewise should be in the S direction.

Inv the construction shown the highly twisted yarn I0 is coiledhelicallyupon a core yarn I3, and when such coreyarn is used it shouldbe weak enough to permit it to be easily broken and thereby permit thetwisted and coiled-yarn I0 to be stretched, or the core yarn Il shouldbe formed of a different type of nbre or filament from that ofthe yarnI0 so that the core yarn I3 may be 'short lengths of yarn.

than twice the diameter of the yarn I0.

After the coiled yarn of Fig.4 1 has had the core I3 removed 'therefromand the yarn I0 is slightly stretched it should have the approximateappearance ofthe openl helical coils shown in Fig. 2. It is desired tomention however, that while a stretchable yarn constructed in accordancewith the present invention should, when relaxed, assume clearlydiscernible convolutions..

such convolutions may be less uniform "in appearance than shown in Fig.2 of the drawing.

In carrying out the present invention it is deemed advisable, at leastin most cases, to so construct the stretchable yarnshown in Fig. 2 ofthe drawing that when it is in the fully relaxed condition it will havea greater number of coils per inch thanl the twists of the crepe yarn I0per inch. When such a construction is employed` the high twist impartedto the yarn I0 will give it considerable stretch, and the coils I2 willimpart to such yarn a much greater stretch.

The action ofthe present yarn shown in Fig. 2 of the drawing is suchthat when it is placed under suilicient tension to straighten it out thetwists imparted to the yarn I0 will increase. as the coils I2 arestraightened out, and as the tension upon the yarn is reduced the coilsI2 will reappear with a corresponding reduction in the twist of the.yarn Ill. It will therefore be seen that the high twist of the yarn Illand the large number of fine helical coils I2 workltogether to impart along range stretch tothe textile yarn.

Furthermore, as above stated the provision of the coils I2 throughoutthe length of the highly twisted yarn I0 prevents the yarn I0 when re'-laxed from kinking to a serious degree, since the coils I2 disperse suchkinks and confine them to This is extremely important because if inhandling. weaving or knitsenseo ting the present yarn it becomes slackand kinks up, these kinks will all disappear as soon as the yarn issubjected to amoderately strong pull.

If the yarn 'I0 is formed of cotton fibers or .viscose rayon then thecore I3 may be formed of cellulose acetate, for example, sinceV such acon--` struction may be treated with acetone which will destroy thecellulose acetate core without injuringthe cotton or viscose rayon yarnI0. The core I3 may be removed either before or afterthe construction ofFig. 1 is embodied in a fabric.

.'It will be understood that as long as the core yam I3 is present itacts as a stop thread and `will hold the twisted coiled yarn I fromstretchtics approaching that of elasticfabric employing rubber threadsin its construction. Should it be` desirable to provide a balanced highstretch yarn in place of the unbalanced high II. Analysis-Before core isremoved Yards per 1h V 7.350 Wrapping:

Twist per inch. 45S Wraps per inch. 1058 Length of yarn in 1 yd. ofcovered core -s -inches-- 119 Gauge -..do .0062

III. Analysis-After removal of core yYards per lb 10,700 Per cent plnngafirm l 85 Per cent elongation at break 170 Tensile strength in grams254 Length of 1 yd. after removing core ..-inches 40 Gauge do .0056

Example of construction shown in Fig. 4 of the drawing:

stretch yarn of Figs.`1, 2.and 3 of the drawing,

this is easily accomplished as will be apparent from Figs. 4,'5 and 6 ofthe drawing, by wrapping aroundthe coils I2 of Fig. 1 an outer coverformed of a highly twisted or crepe yarn I4 so as `to form the helicalcoils I5 that surround the coils I2. It is highly importanthowever, thatthe twist of the yarn Il shall be in the opposite direction to the twistof the yarn I0, 'and that the helical winding I5 shall be in the samedirection as the twist of the yarn I4 but in the opposite direction tothat of the windings I2. The yarn I4 may be made of the same textilematerial as the yarn I0 or a different textile material as desired. Forexample the yarn III may be formed of cotton and the yarn I4 may beformed of viscose'rayon to improve the appearanceand feel of the nishedstretchable yarn. After the core I3 is removed from the constructionshown in Fig. 4 and the balanced yarn is partly stretched it shouldappear more or less as shown in Fig. 5 of the drawing.4 i

l'lhe construction shown in Fig. 1 may be produced on a covering machineof a type which has `been extensively used heretofore to wind a coverabout a rubber core to produce an elastic yarn of the single cover type.'Ihe construction shown in Fig. 4 of the drawing may be produced on asimilar covering machine adapted to wind a right and left hand coverabout a central core.

Instead ofwinding an outer cover over the inner cover as shown in Figs.4, 5 and 6, to produce a balanced construction, a balanced highlystretchable yarn may be produced as shown in Figs. 7 and 8. This isaccomplished by employing two yarn constructions such as shown in Fig.lof the drawing and twisting them together as shown in Fig. 7 with a plytwist, but it is important that this ply twist be in the oppositedirection to that of the Winding of the coils I2. After the constructionof Fig. 7 is made the core yarns I3 should be removed. g

r In order that the constructions of the present invention may befurther understood, the following examples are given:

Example of construction shown in Fig. 1 of the drawing:

I. Construction Core: 1 end of 150 den., acetate yarn Wrapping: 1 end of80 S/2, cotton yarn Twist multiplier o1' wrapping yarn 7.1

' I. Construction Core: 1 end of 150 den., acetate yarn v Firstwrapping: 1 end of 80 S/2, cotton yarn Twist multiplier of firstwrapping, 91.5

Second wrapping: 1 end of 150 den., viscose yarn Twist multiplier ofsecondwrapping: 8.1

II. Analysis- Before core is removed Yards per lb 2,540 First wrapping:

Twist per inch.. 60S Wraps `per inch ..-t 1158 Length of yarn in 1 yd.of covered core s inches-- 138 Second wrapping:

' Twist per inch 48Z Wraps per inch 1132 Length of yarn in 1 yd. ofcovered core inches-; 230 Gauge do .022

III. Analysis-After removal of core Yards per lb 4.560 Per centelongation. 110 Per cent elongation at break Tensile strength in grams256 length of 1" yd. after removing core inches-- i 37 Gauge do .019

Example of construction shown in Fig. 7 of the drawing:

- I. Construction Core: 1 end of 150 den., acetate yarn Wrapping: 1 endof 80 S/2, cotton yarn Ply twist: 2 ends of the Fig. 1 constructiontwisted together II. Analysis-Before core is removed A highlystretchable yarn construction in accordance with the present inventionwill have a lower. elastic modulus and slower recovery than a rubbercovered elastic yarn, but this may be desirabletor use in some wearingapparel such for example as in light weight under-garments, bathingsuits, tops of stockings, waist bands, etc. I'he present stretchableyarn has the further advantages over elastic yarn containing rubber inthat it may be repeatedly washed or dry cleaned without injury, and isfree from the odor of rubber. It also should give good wear and retainits stretchable characteristics until it is worn out.

, The term crepe twist has been herein used as meaning a twistconsiderably higher than ordinary yarn twist, and as including a widertwist 5. An all-textile yarn having high stretch char. acteristics,comprising a crepe yarn having superposed thereupon inthe same directiona higher number of contacting helical coils per inch than the crepetwists per inch, whereby the yam 6. A. balanced all-textile yarn havinghigh stretch characteristics, comprising a yarn having a crepe twist andwhich in this highly twisted condition is coiled helically about acentral axis in spaced relation thereto and in the direction in which itis twisted, a second yarn having a crepe twist in the opposite directionand wound range than that indicated by the three twist multipliers givenin the -above tables.

' Having thus described my inventionf what I claim and4 desire toprotect by Letters Patent is:

1, An all-textile yarn having high stretch chara'cteristics, comprisinga yarn having a crepe twist and which in this highly twisted conditionis coiled helically about a central axis in the direction it is twisted,so that it has in itsrelaxed condition a diameter that is more thantwice the diameter of the uncoiled yarn .and a greater number of helicalcoils per inch than the twists of the crepe yarn per inch forming suchhelix.

2. An all-textile yarn having an elastic exi tensibility range inexcessof 50 per cent, -comprising a yarn having a crepe twist and which inthis highly twisted condition is coiled helically about a central axisin spaced relation thereto and in the direction in which it is twisted.so that it has in its relaxed condition la greater number of helicalcoils per inch than the twists of the crepe yarn per inch forming suchhelix.

3. An al1-textile yarn having high stretch characteristics, comprising a-yarn having a crepe twistand which in this highly twisted condition iscoiled helically about a 'central axis in the -direction in which it istwisted, so that it has in its relaxed condition a' diameter that ismore than twice the diameter of the uncoiled yarn and in addition thishighly twisted condition is coiled helically about a central axis inspaced relation theretoy and in the direction in which it is twisted sothat it has in its relaxed condition a large numtwist.

helically over the coils of the nrst yarn, but in the opposite directionto said first coils, and each of said crepe twisted yarns having in therelaxed condition a. large number of helical coils.

7. A balanced all-textile yarn having an elastic extensibility range inexcess of per cent, comprising a yarn having a crepe twist and which inthis highly twisted condition is coiled helically about a central axisin spaced relation thereto A and in the direction in which lt istwisted, a. second yarn having a crepe twist in-the opposite directionand wound as a cover helically over the coils of the first yarn but inthe opposite direction to said first coils, and each of said crepetwisted yarns having in the relaxed condition a large number of helicalcoils.

'8. A balanced all-textile yarn having high stretch characteristics,comprising two crepe yarns each of which is twisted in the samedirection and which in its highly twisted condition is coiled helicallyin the direction in which it. is twisted to form two separatestretchable yarns each of which in the relaxed condition has a largenumber of line coils in addition to its high twist, and said twisted andcoiled yarns being twisted together in the opposite direction to form abalanced highly stretchable ply yarn.

9. An all-textile yarn. having high stretch characteristics, comprisinga plurality of crepe yarns each of which is twisted and helically coiledy inthe same direction to form separate stretchable yarns, each of whichin the relaxed condition has a large number of ilne coils in addition toits high twist, and said twisted and coiled yarns being twisted togetherin the opposite direction to form a substantially balanced and highlystretchable ply yarn. IBOUTWELL H. FOSTER.

